Abstract: A numerical control information generating system prevents a tool from interfering with a work when the tool is moved from a tool change position to a cycle start point or from a cycle end point to the tool change position by setting a step start point and a step end point for each machining step outside of a before-machining shape, and classifying the positional relation of the shape upon completion of machining with the machining steps into the outer face, inner face, the front face, the outer rear face and the inner rear face so that based on the information denoting the positional relation the paths of the tool from the tool change position to the step start point or from the step end point to the tool change position are determined. When a same tool is used for machining in plural sequential steps, the time required to move the tool between the step to another can be shortened since the tool is moved from the end point of a step to the start point of the subsequent step.

Abstract: When a position of a tool blade tip for displaying the work shape, tool shape and tool locus is calculated by an interpolation arithmetic operation based on the interpolation instruction and feed speed instruction within a numerical control data, the calculated position of the tool blade tip is compared with the display scope every time an interpolation arithmetic operation is conducted; a determination is made as to whether or not the tool shape and tool locus to be displayed are inside of the display scope, and when they exist outside, uses a higher speed as the feed speed for the interpolation arithmetic operation. Therefore, even when an operator tries to check numerical control data by reducing the display scope for local graphic display, the interpolation outside the display scope can be conducted at a higher speed to thereby allow the operator to check the numerical control data quickly and immediately.